Method of washing with linear alkyl vicinal disulfates

ABSTRACT

R AND R1 ARE HYDROGEN OR ALKYL RADICALS HAVING A TOTAL OF FROM 9 TO 23 CARBON ATOMS, AND X IS HYDROGEN OR A WATERSOLUBLE SALT-FORMING CATION.   -S, -S(=O), OR -S(=O)2   IN WHICH Y IS   R-CH(-R1)-(Y)-CH2-CH(-O-SO2-X)-CH2-O-SO2-X   METHOD OF WASHING FABRICS IN THE ABSENCE OF PHOSPHATE BUILDERS EMPLOYING DETERGENT ACTIVE MATERIALS WHICH COMPRISE SULFUR-LINKED LINEAR VICINAL DISULFATES OF THE FORMULA:

3,714,076 METHOD OF WASHING WITH LINEAR ALKYL VHCINAL DISULFATES RobertG. Anderson, San Rafael, Calilh, assignor to Chevron Research Company,San Francisco, Calif. N Drawing. Original application Aug. 5, 1970, Ser.No. 62,233, new Patent No. 3,651,119. Divided and this application Sept.23, 1971, Ser. No. 183,239

Int. Cl. (111d 1/12 US. Cl. 252550 4 Claims ABSTRACT OF THE DISCLOSUREMethod of washing fabrics in the absence of phosphate builders employingdetergent active materials which comprise sulfur-linked linear alkylvicinal disulfates of the formula:

\ OSOaX R and R are hydrogen or alkyl radicals having a total of from 9to 23 carbon atoms, and X is hydrogen or a watersoluble salt-formingcation.

CROSS-REFERENCE TO RELATED APPLICATION This application is a division ofUS. application Ser. No. 62,233, filed Aug. 5, 1970, now Pat. No.3,651,119.

BACKGROUND OF THE INVENTION This invention is concerned withsulfur-linked linear alkyl vicinal disulfates which are effective asheavy duty detergent active material.

Increased concern over Water pollution has produced significant changesin household detergents. Initially, major emphasis has been placed onproducing biodegradable surface-active components for detergents. Theshift to linear surface-active materials, including linear alkylbenzenesulfonate (LAS) and alpha-olefin sulfonates, etc.,

has reduced pollution attributed to nonbiodegradability. i

However, the above-mentioned surface-active materials are inadequate interms of soil removal in the absence of phosphate builders. Increasingevidence appears to indicate that phosphates contribute to the growth ofalgae in the nations streams and lakes. This algae growth poses a seriespollution threat to the maintenance of clear, good domestic watersupplies.

Consequently, there has developed a need for detergent active materialswhich will function successfully in the absence of phosphate builders.Recently, certain non-phosphate building materials have been proposed areplace ments for the phosphates. Thus, materials such as the polysodiumsalts of nitrilotriacetic acid, ethylene diamine tetraacetic acid,copolymers of ethylene and maleic acid, and similar polycarboxylicmaterials have been proposed as builders. These materials, however, whenemployed with conventional detergent actives such as LAS, have, for onereason or another, not proved to be quite as ef- States Patent3,7l4hh'76 Patented Jan. 30, 1973 fective as phosphates in detergentformulations. For eX- ample, some of the materials have proven to beinsufiiciently biodegradable to meet present and anticipatedrequirements.

It is therefore desirable to provide compounds which are effective asdetergent active materials in the absence of phosphate builders and arealso sufiiciently biodegradable that their use results in contributingneither foam producers nor phosphates to the water supply.

SUMMARY OF THE INVENTION Effective heavy duty detergent compositionswhich may be formulated without the necessity of phosphate builders areprovided. These formulations employ as detergent active materialssulfur-linked linear alkyl vicinal disulfates of the formula:

R and R are hydrogen or alkyl radicals having a total of from 9 to 23carbon atoms, and X is hydrogen or a watersoluble salt-forming cation.In a preferred form Y is DESCRIPTION OF PREFERRED EMBODIMENTS Thesalt-forming cation X may be any of numerous materials such as alkalimetal, alkaline earth metal, ammonium, or various organic cations.Examples of suitable organic cations include amino materials such asthose of the following structure:

The alkali metal cations are preferred, and sodium ions are particularlypreferred.

The aryl groups represented by R and R are, as previously noted, linear,although the presence of a random methyl radical upon the linear chain,for example, may not adversely affect the performance of the compound.Alkyl radicals representative of R and R includes hexadecyl, heptadecyl,octadecyl, nonadecyl, eicosyl, heneicosyl, and docosyl. Heptadecyl,octadecyl, nonadecyl, eicosyl, and heneicosyl groups are preferred. In apreferred form the materials are formed by the reaction of thioglycerolwith an alpha olefin and thus one or the other of R and R will behydrogen.

The detergent active compounds of this invention are preferably preparedby reacting a linear monoolefin, preferably an alpha olefin, withthioglycerol giving a compound having two vicinal hydroxy groups. Thehydroxy groups are then sulfated by conventional techniques giving acompound containing two sulfate groups and a sulfide linkage in thebackbone. This compound, while being an adequate detergent, is sensitiveto bleaching and in the preferred embodiment the sulfide prior tosulfation is oxidized to a sulfoxide or a sulfone or a mixture thereof.The products then obtained by sulfation are excellent detergents and arebleach stable.

The reaction of the olefin and the thioglycerol is accomplished bysimply heating the materials together followed by recrystallization fromconventional solvents such as ethanol or benzene. The sulfation of thedioxy compound is elfected by conventional sulfation techniquesemploying sulfur trioxide, chlorosulfonic acid, oleum, sulfuric acid,etc., in a ratio of at least 2 mols of sulfating agent per mol of diol.Ratios of from 2 to 10 are preferred. When it is desired to oxidize thesulfide group prior to sulfation, this is accomplished again byconventional techniques employing as oxidizing agents hydrogen peroxide,metal hypohalites, etc.

The following examples illustrate the preparation of the compounds ofthis invention.

EXAMPLE 1 Addition of thioglycerol to l-hexadecene A 500 ml. flask wascharged with 112 g. (0.5 mol) of l-hexadecene, 71.5 g. (0.6 mol) ofthioglycerol, and 100 ml. of ethanol. The mixture was placed upon a hotplate and heated overnight at 50-70 C. The mixture, originally in twolayers, had become homogenous. It was allowed to cool to roomtemperature and then further cooled with ice. The solid product in theflask was removed by filtration and recrystallized from ethanol. Theproduct was dried in a 50 C. oven overnight and gave a yield of 126 g.of a white solid which melted at 71-72 C. and by IR analysis showed twotypes of --OH absorption and no remaining olefin bonds.

EXAMPLE 2 Addition of thioglycerol to l-eicosene The procedure ofExample 1 was followed employing 140 g. (0.5 mol) of l-eiconsene insteadof hexadecene. After recrystallization from ethanol there was obtained166.6 g. (85.9% yield) of a white solid which showed by IR analysis twotypes of -OH absorption and the presence of a small amount of alphaolefin. The product was recrystallized from benzene to give a whitesolid, melting point 82-83.5 C., an IR analysis of which showed noremaining olefin bonds.

EXAMPLE 3 Addition of thioglycerol to l-docosene The procedure ofExample 1 was followed employing 154 g. (0.5 mol) of l-docosene. Theproduct recrystallized from benzene was 183 g. (88% yield) of a whitesolid having a melting point of 87-88 C.

EXAMPLE 4 Oxidation of eiconsene-thioglycerol adduct 15.1 g. (0.039 mol)of the product of Example 2 and 60 ml. of glacial acetic acid wereplaced in a 125 ml. flask equipped with a magnetic stirrer. Athermometer was inserted and 10.5 ml. (0.084 mol) of 30.6% H was addedslowly and with stirring. The maximum temperature reached without theapplication of external heat was 50 C. The temperature was raised to 80C. and maintained for 1% hours. The mixture was cooled in ice and theproduct collected by suction. The white solid thus obtained wasrecrystallized from benzene to give 14.7 g. (90.0%

yield) of produc a White needles, melting 112-113 C.,

whose IR spectra showed a strong band at 1120 cm. (SO and nothing atabout 1000 cm. (SO-).

EXAMPLE 5 Sulfation of oxidized hexadecene-thioglycerol adduct with 50;;

276 mg. (0.6 mmol) of a sulfone-containing material prepared accordingto the procedure of Example 4 from the product of Example 1 was placedin a ml. stoppered graduated cylinder containing 10 ml. of CCl.; and amagnetic stirring bar. The mass was heated to dissolve, then stirred andplaced in an ice bath. The precipitate was uniformly fine. Afterflushing with N 0.1 ml. of 50;, was added dropwise to the coldsuspension. The mixture turned yellow and dissolved. The cylinder wasremoved from the ice and an additional 0.1 ml. of S0 was added dropwise.The color darkened. A 1 ml. sample was titrated with Hyamine showing thepresence of 1.9 sulfate groups per molecule. The CCl was removed fromthe remainder of the solution, water was carefully added, and the wholewas neutralized to a pH of 10 (pH meter) with NaOH solution.

EXAMPLE 6 Sulfation of sulfoxide-containing octadecene thioglyceroladduct 0.5 g. of an adduct of l-octadecene with thioglycerol preparedaccording to the procedure of Example 1 and oxidized to contain onesulfoxide group per molecule was placed in a 250 ml. beaker anddissolved in 40 ml. of dry methylene chloride. After cooling the mixtureto 10 C., 1.0 ml. of chlorosulfonic acid was slowly added by submergingthe tip of an eyedropper containing the acid below the surface of thewell agitated solution. The resulting solution was allowed to stand atambient conditions for five minutes. The pH was adjusted to 8-9 withdilute sodium hydroxide. The solvent was removed by gentle warming andthe residue diluted to 100 ml.

EXAMPLE 7 Sulfation of eicosene-thioglycerol adduct with chlorosulfonicacid A ml. Erlenmeyer flask was charged with 0.5 g. (1.29 mmoles) of theproduct of Example 2 and 40 ml. of dry diethyl ether. After cooling themixture to 10 C., 1.0 ml. of chlorouslfonic acid was slowly added bysubmerging the tip of an eyedropper containing the acid below thesurface of the well agitated other solution. The resulting solution wasallowed to stand at ambient conditions for five minutes. The pH wasadjusted to 8-9 with dilute sodium hydroxide. The solvent was removed bygentle warming and the residue diluted to 100 ml.

Detergency of the compounds of the present invention is measured bytheir ability to remove natural sebum soil from cotton colth. By thismethod, small swatches of cloth, soiled by rubbing over face and neck,are washed with test solutions of detergents in a miniature laboratorywasher. The quantity of soil removed by this washing procedure isdetermnied by measuring the reflectances of the new cloth, the soiledcloth, and the Washed cloth, the results being expressed as percent soilremoval. Because of variations in degree and type of soiling, in waterand in cloth, and other unknown variables, the absolute value of percentsoil removal is not an accurate measure of detergent effectiveness andcannot be used to compare various detergents. Therefore, the art hasdeveloped the method of using relative detergency ratings for comparingdetergent effectiveness.

The relative detergency value is obtained by comparing and correlatingthe reflectance value results from the test solution with the resultsfrom two defined standard solutions.

The two standard solutions are selected to represent a detergentformulation exhibiting relatively high detersive characteristics and aformulation exhibiting relatively low detersive characteristics.

By testing experimental solutions against the two stan dardizedsolutions, using different portions of the same soiled cloth, theresults can be accurately correlated. The two standard solutions wereprepared from the following detergent formulations:

Formulation for the low detersive standard (Control A) Ingredient:Weight percent Alkylbenzene sulfonate 35 Sodium triphosphate 40 Water8.5 Sodium sulfate 8 Sodium silicate 7 Carboxymethylcellulose 0.8

Formulation for the high detersive standard (Control B) Ingredient:Weight percent Linear alkylbenzene sulfonate (LAS) 7.5 Tallow alcoholsulfate 10 Sodium triphosphate 47.5 Water 10 Sodium sulfate 13 Sodiumsilicate 5 Carboxymethylcellulose l The standard exhibitinghigh-detersive characteristics was prepared by dissolving a relativelylarge amount of the above formulation (Control B) (2.0 g.) in 1 liter of300 p.p.m. hard water (calculated as -73 calcium carbonate and 6magnesium carbonate). The low detersive standard contained a relativelow concentration of the formulation (Control A) (1.0 g.) dissolved in 1liter of 300 p.p.m. water (same basis).

The miniature laboratory washer used was so constructed that the twostandard formulations and two test formulations could be used to washdifferent parts of the same swatch. This arrangement ensured that allfour formulations were working on identical soil (natural facial soil).Relative detergency (RD) values were calculated from soil removals (SR),according to the equation:

Percent S B -Percent S Rcmml A RD=2+4 Percent SR -Percent SR A an LAS(20%)/sodium triphosphate (40%) conventional built detergent was 5.8 at0.1% and 6.1 at 0.2% concentration (50 p.p.m. water hardness). Thesematerials were tested in formulations containing 7% sodium silicate, 1%carboxymethylcellulose, 8% water, the indicated amounts of LAS andphosphate, and sufiicient sodium sulfate to give 100%.

The sulfur-linked alkyl vicinal disulfates may be employed incombination with other detergent active materials. They are particularlyeffective with other dianionic materials, examples of which includelinear alkyl and alkenyl disulfates and disulfonates. A particularlyuseful class of materials for use in detergent active combinations isthat of linear 2-alkenyl or linear 2-alkyl 1,4-butane diol disulfates inwhich the alkenyl or alkyl groups contain from 15 to 20 carbon atoms.

In employing the detergent active materials of this invention indetergent compositions, they may be formulated with additionalcompatible ingredients being optionally incorporated to enhance thedetergent properties. Such materials may include but are not limited toanticorrosion, antiredeposition, bleaching and sequestering agents, andcertain organic and inorganic alkali metal and alkaline earth metalsalts such as inorganic sulfates, carbonates, or borates. Alsononphosphate builders may be included in the composition. Examples ofthese builders are the sodium salts of nitrilotriacetic acid, ethylenediamine tetraacetic acid, and ethylene maleic acid copolymers, etc. Alsosmall quantities of phosphate builders may be included although, ofcourse, they are not necessary for effective detergency.

While the character of this invention has been described in detail withnumerous examples, this has been done by way of illustration only andwithout limitation of the invention. It will be apparent to thoseskilled in the art that modifications and variations of the illustrativeexamples may be made in the practice of the invention within the scopeof the following claims.

What is claimed is:

1. In a method of washing fabric by contacting said fabric with anaqueous solution containing a detergent amount of detergent activematerial under conditions of time and temperature to eflfect substantialsoil removal from the fabric, the improvement which comprises carryoutthe washing in the absence of phosphate builders and employing asdetergent active material sulfur-linked linear alkyl vicinal disulfatesof the formula:

RELATIVE DETERGENCY OF ALKYL VICINAL DISULFATES Relative detergencyratings in The relative detergency rating for linear alkylbenzenesulfonate (LAS) (25%) was 2.9 at 0.1% and 3.9 at 0.2%

R and R are hydrogen or alkyl radicals having a total of from 9 to 23carbon atoms, and X is hydrogen or a concentration (50 p.p.m. waterhardness). The rating for water-soluble salt-forming cation.

7 8 2. The method of claim 1 in which Y is FOREIGN PATENTS 0 1,151,3925/1969 Great Britain 252558 g 6,709,714 1/1968 Netherlands 260458 H 0 5LEON D. ROSDOL, Primary Examiner 3. The method of claim 1 in which X isalkali metal. 4. The method of claim 3 in which X is Na. P E, WILLIS,Assistant Examiner References Cited Us. CL UNITED STATES PATENTS 10 -52,645,659 7/1953 Morris et a1. 260458 X

